The Cytopathology Section provides complete diagnostic service in exfoliative cytology and fine needle aspiration cytology. The section also routinely applies immunocytochemistry techniques to confirm and/or enhance cytological diagnostic accuracy. In addition, the section collaborates in various clinical research projects utilizing routine microscopy as well as special staining techniques and immunocytochemistry. The fine needle aspiration service is designed to afford maximal flexibility for clinicians and patients. Clinicians may request that: 1) a pathologist perform the aspiration; 2) a cytotechnologist assist the clinician in handling the specimen; 3) aspirations of deep lesions be performed by the radiologist with the assistance of a cytotechnologist to evaluate adequacy of the specimen. The Cytopathology Section initiates and collaborates in various clinical research projects. A partial listing of recent and/or ongoing projects includes: (1) Evaluation of percent of tumor cells expressing CD22 in FNA specimens as part of a clinical trial using monoclonal antibody therapy for refractory CD22 positive lymphomas; (2) Evaluation of expression of drug resistance marker P-glycoprotein prospectively by FNA in breast cancer patients treated with new combination chemotherapy; (3) characterization and application of a novel murine monoclonal antibody for malignant melanoma, MART-1 with subsequent quantitation of MART-1 in FNAs from malignant melanoma patients for treatment with anti-MART-1 antibody; 4) morphologic and immunocytochemical evaluation of bone marrow specimens from patients with stage IV breast cancer; 5) immunocytochemical evaluation of lymphoid populations in bronchoalveolar lavage specimens from patients subsequent to local exposure to endotoxin. Another collaborative project with the Whitman-Walker AIDS clinic is evaluating the prevalence of cervical premalignant lesions in HIV infected women.